1. Field of the Invention
The present invention relates to an inkjet discharge method and a pattern formation method using the discharge method. Furthermore, the present invention relates to a pattern formed by the pattern formation method.
2. Description of the Related Art
The imprinting method is a technique of transferring a fine pattern to a material by pressing a metal mold (generally referred to as a mold or a stamp), in which a pattern is formed, on the material. By using the imprinting method, a precise fine pattern can be prepared in a simple manner. Therefore, in recent years, the application of the method in various fields has been expected. Particularly, a nanoimprinting technique forming a nano-order fine pattern has drawn attention.
As the imprinting method, those called a thermal imprinting method and a photoimprinting method according to the transfer method have been suggested. In the thermal nanoimprinting method, a fine pattern is formed by pressing a mold on a thermoplastic resin heated to a temperature of equal to or higher than the glass transition temperature, cooling the resin, and then releasing the mold. In this method, various materials can be selected. However, the method also has problems in that a high pressure is required at the time of pressing, and a fine pattern is not easily formed because of thermal contraction or the like.
In contrast, in the photoimprinting method, in a state in which a mold is pressed on a photocurable composition, the composition is cured by light, and then the mold is released. In this method, high-pressure and high-temperature heating does not need to be performed for carrying out imprinting on an uncured substance, and a fine pattern can be prepared in a simple manner.
In the photoimprinting method, a substrate (subjected to adhesion processing if necessary) is coated with a photocurable composition, and then a mold prepared by using a light-transmitting material such as quartz is pressed on the composition. In a state in which the mold is pressed on the photocurable composition, the composition is cured by being irradiated with light, and then the mold is released. In this way, a cured substance to which an intended pattern has been transferred is prepared. In the photoimprinting method, in order to obtain a pattern which exhibits excellent transferability, the release properties between the mold and the photocurable composition needs to be improved. Furthermore, in a case in which micromachining is performed by using the transferred imprinting pattern as a mask, control of a residual film (forming a thin film and achieving uniformity) is required.
As the method for applying the photocurable composition onto the substrate, a spin coating method and an inkjet method are exemplified. Particularly, the inkjet method has drawn attention recently as the application method because loss of the photocurable composition is small.
As the method for improving the release properties, WO2005/000552A discloses adding a surfactant to the photocurable composition. In WO2005/000552A, a surfactant, which is localized in a mold, is added to the photocurable composition so as to control the interfacial affinity between the mold and the cured photocurable composition, thereby improving the release properties.
Furthermore, JP2011-021113A discloses a composition obtained by adding an oligomer-type surfactant to a photocurable composition at a high concentration.
Meanwhile, JP2012-67203A describes an ink discharge method for an inkjet.